I just got a FM transmitter and antenna (Don't worry, the antenna didn't come with the transmitter), and I tested it out. There is a lot of line noise, and the signal is a little bit distorted. Is there any way I can fix this?
Let's start with some basics.......What make/model transmitter? Make/model of antenna? Feedline type -- coax? Hardline? Type of connectors? Audio source(s)? Are you running an audio board or just, say, plugging in a CD player/mic, etc.?? Noise can - and DOES - come from a myriad of sources....Knowing WHAT you have for equipment and HOW it's hooked up will go a long way in helping to determine issues like distortion and "line noise"..... Post back with more info and you'll likely get some helpful response!! Good Luck!
The transmitter I am using is the CZERF CZE-15A, along with an unbranded antenna. Here's a link to the antenna that I bought: goo.gl/pOUnB1. My audio sources are my computer and sometimes my mixer. I am using the BNC cable that came connected to my antenna. The antenna is a bit wobbly, not sure if that makes a difference.
For starters....that transmitter is set up for 50uS pre-emphasis! The US standard is 75 uS......unless you rework the audio section (replacing a couple of caps and resistors) you'll have distortion on the received signal using an FM receiver set for 75 uS... Unless you're REALLY GOOD at micro-soldering/de-soldering, modding this transmitter to 75 uS is a virtual "no-go"!!! Trust me....I have one of these and attempted the "mod"...TWICE!! I gave up before I ruined the printed circuit board!! Nearly ALL these cheap Chinese transmitters are set up for 50 uS....you CAN find a couple with 75 -- and one or two WILL make the conversion prior to shipping...BUT YOU NEED TO REQUEST THIS at the time you order!!! As for the antenna.....ALL FITTINGS SHOULD BE TIGHT!! NOTHING SHOULD BE "WIGGLING" OR LOOSE!! Use the best quality coax and connectors you can!! Buy or borrow a GOOD SWR bridge to check for high reflected power -- usually the sign of a mis-tuned antenna, which can (and often DOES!) result in damage to the RF output transistor(s)! End of the day.....everyone wants to save a buck.......I'm in that boat (retired, fixed income)....but I've found you just WON'T be really happy with these cheapo Chinese "toys"!! Check out eBay for "FM BROADCAST TRANSMITTER" or "....EXCITER"....Look for something made in (or at least FOR) the USA....I've scored a CCA 20-G exciter, a QEI 675-T20 and a Wavemach FM-25WS here....granted, they were somewhat more expensive than your CZ unit....but they're built like brick S*** houses and will last FOREVER with proper care! Finally....what I said about coax and fittings also applies to AUDIO cables....Monoprice puts out some GREAT stuff at super low cost -- practically ALL my audio cables and adapters have come from them!! Try to find a mixer/console with 600 ohm outputs (ie., XLR connectors) rather than RCA phono plugs/jacks; they tend to be MUCH quieter overall... REMEMBER!! QUALITY does NOT have to come with a huge price tag!!! You DO need to shop around and scope out the best deals YOUR budget will allow.... Good Luck!
